Merge pull request #733 from olivervogel/master

added before_install command

.travis.yml

@@ -16,6 +16,7 @@ matrix:
 
 before_install:
   - sudo add-apt-repository -y ppa:moti-p/cc
+  - sudo apt-get clean
   - sudo apt-get update
   - sudo apt-get -y --reinstall install imagemagick
   - yes | pecl install imagick-beta